<link href="//cdn.bootcss.com/select2/3.5.4/select2.min.css" rel="stylesheet"/>

<script src="//cdn.bootcss.com/jquery/1.7.1/jquery.min.js"></script>

<script src="//cdn.bootcss.com/select2/3.5.4/select2.min.js"></script>

<input type="hidden" id="e20" style="width:300px" value="brown"/>

<script>

    $("#e20").select2({

        tags:["red", "green", "blue"],

        tokenSeparators: [",", " "]});

</script>